Michael Poland

Map of seismicity (red circles) in the Yellowstone region during 2023. Gray lines are roads, black dashed line shows the caldera boundary, Yellowstone National Park is outlined by black dot-dashed line, and gray dashed lines denote state boundaries.

Infrasound-array processing for the newly installed station YNB, at Norris Geyser Basin. Top panel shows the pressure waveform from one of the three elements that comprise the array, filtered between 1 and 15 Hz. Bottom panel shows the backazimuth from the station to the source.

River levels and vertical deformation of Yellowstone caldera during 2016–2022.  River level (blue) was measured at the Corwin Springs gaging station on the Yellowstone River, just north of Yellowstone National Park.  Vertical deformation (red) is from the WLWY GPS station on the east side of Yellowstone caldera.  The GPS data indicate overall subsiden

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Photo of Devil’s Slide, Montana, looking across the Yellowstone River.  The red streak is a Triassic shale layer.  Rocks to the right of the streak are older and to the left are younger.  USGS photo by Mike Poland, August 2, 2023.

Streamgage site and profiling tool on the Yellowstone River at Corwin Springs, Montana.  The gage house narrowly avoided damage during the June 2022 flood, which eroded the downstream bank.  The river profiling instrument helps to map the river bottom to assess streamflow rates and conditions.  USGS photo by Mike Poland, July 31, 2023.

Visible (top) and thermal (bottom) images of Porcelain Basin looking to the north from the old roadbed.  Nuphar Lake is off the photograph to the right.  Cool-water seeps into Porcelain Basin are clearly evident in the thermal image and appear to flow underground from Nuphar Lake.  USGS photos by Mike Poland, July 1, 2023.

High-resolution satellite images of the Porcelain Basin and Nuphar Lake areas of Norris Geyser Basin acquired by Quickbird-2 on September 11, 2006 (left), WorldView-3 on July 7, 2016 (middle), and WorldView-3 on March 30, 2022 (right).  Note the change in color of Nuphar lake, from deep green to light blue, over time, as well as the increased evidence of flow f

Map of Norris Geyser Basin showing the locations of major subbasins, roads and trails, and Nuphar Lake.

High-resolution satellite images of the Porcelain Basin and Nuphar Lake areas of Norris Geyser Basin acquired by Quickbird-2 on September 11, 2006 and WorldView-3 on March 30, 2022.  Note the change in color of Nuphar lake, from deep green to light blue, over time, as well as the increased evidence of flow from thermal features on the east side of Porcelain Bas

Earthquake Lake, which formed when the Madison River was blocked by a landslide that occurred as a consequence of the Hebgen Lake earthquake in 1959.  The lake inundated existing forest, now marked by standing dead trees in the lake water. The landslide scar is visible on the side of the mountain at the far end of the lake.

Map of continuous Global Positioning System (GPS), semipermanent GPS, borehole strainmeters, and borehole tiltmeters that provide surface deformation monitoring capability in and around Yellowstone National Park. Red line denotes boundary of Yellowstone Caldera.

Distribution of hydrothermal features in Yellowstone as a function of their pH (modified and updated from Nordstrom et al., 2009). There are two distinct groupings: one is more acidic, and the other neutral to basic.

Soil carbon dioxide concentration and temperature measured at a new thermal area near Tern Lake in Yellowstone National Park on the east side of Yellowstone Caldera. A, Map of soil carbon dioxide flux simulated based on measurements made at the black dots in September 2022. B, Map of soil temperature at a depth of 20 centimeters (8 inches).

Front cover of the Yellowstone Volcano Observatory 2022 annual report, which includes a summary of earthquake, deformation, and geyser activity, as well as research investigations and other information.